The Java language is one of the most commonly used object-oriented programming languages ??in the world today. The concept of class is one of the most important features in object-oriented languages. A class is like a blueprint for an object. For example, when we want to build a house, we first create a blueprint of the house, in other words, we create a plan that shows how we are going to build the house. According to this plan we can build many houses. Likewise, using classes, we can create many objects. Classes are blueprints for creating many objects, where objects are real-world entities like cars, bikes, pens, etc. A class has the characteristics of all objects, and the objects have the values ??of these characteristics. In this article, we will write a Java program to find the perimeter and area of ??a rectangle using the concept of classes.

A class includes the following contents ?

• Data members - Data members represent the characteristics/properties of the object collection

• Methods - Methods represent operations performed by an object.

For example, if we regard a person as a class, then attributes such as name, age, and address are data members, and actions such as sitting, standing, eating, and walking are methods of the class.

Syntax for creating classes

class ClassName
{
   //data members
   //methods
}

Class names always start with a capital letter. For example, Person, House, Bank, etc.

Example

class Person{
   //data members
   String name;
   int age;
   String city;
   //methods
   void read(){
      System.out.println(“Reading”);
   }
}

Syntax for creating objects

ClassName objectname = new ClassName();

Example

Person person_one =new Person();

Perimeter of the rectangle

The perimeter of a rectangle is the total area enclosed by the four sides of the rectangle, that is, the area covered by the length and width of the rectangle.

formula

Perimeter of the rectangle 
= area covered by the sides of the rectangle
= 2(l+w)
where,  l : length of rectangle
        w : width of rectangle

Area of ??rectangle

The area of ??a rectangle is the total space occupied by the rectangle on a two-dimensional plane.

formula

Area of the rectangle 
= area covered by the rectangle
=  l*w
where , l : length of rectangle
             w : width of rectangle

algorithm

Step 1 ? Create a custom class named Rectangle, which has "area()" and "perimeter()" methods. These functions give the area and perimeter of the rectangle as output respectively.

Step 2 ? Now, create a rectangular object using the constructor in the main class.

Step 3 ? Now call the corresponding functions to find the area and perimeter of the rectangle using the created object.

Example

In this example, we created a custom Rectangle class with "area()" and "perimeter()" methods. Then, use the constructor of the main class in the main class to create an object of the Rectangle class, and call the corresponding methods area() and perimeter() on the created object. Once the methods are called, they are executed and the output is printed.

// Java program to calculate  the area and perimeter of a rectangle using class concept
import java.util.*;
// Rectangle Class File
class Rectangle {
    // data members
    int length, width;
    // methods
    //constructor to create Object
    Rectangle(int length, int width) {
        this. length = length;
        this.width = width;
    }
    // prints the area of rectangle
    public void area() {
        int areaOfRectangle;
        areaOfRectangle = this.length * this.width;
        System.out.println("Area of rectangle with the given input is : " + areaOfRectangle);
    }
    // prints the perimeter of rectangle
    public void perimeter() {
        int  perimeterOfRectangle;
        perimeterOfRectangle = 2 * (this.length + this.width);
        System.out.println("Perimeter of rectangle with the given input is : " + perimeterOfRectangle);
    }
}
public class Main {
    public static void main(String args[]) {
        Rectangle rect_obj = new Rectangle(10,5);  // obect creation
        System.out.println("Length = " + rect_obj.length);
        System.out.println("Width = " + rect_obj.width);
        rect_obj.area(); // returns area of rectangle
        rect_obj.perimeter(); //returns perimeter of rectangle
    }
}

Output

Length = 10
Width = 5
Area of rectangle with the given input is : 50
Perimeter of rectangle with the given input is : 30

Time complexity: O(1) Auxiliary space: O(1)

So, in this article, we learned how to implement Java code using the concept of classes to find the area and perimeter of a rectangle.

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